Glass Substrate with High Density Electrical Feedthroughs

This paper reports a novel method to produce high density feedthrough glass wafers with sufficient thickness for the packaging and interconnection of high density array micro electromechanical systems (MEMSs). Pyrex glass wafers with thin film metal lines on the surface are stacked and bonded with each other using phenyl methyl siloxane-based adhesive. The stacked glass wafer block is then sliced using a wire saw as the slicing surfaces vertically cross the adhesive bonding interfaces. Prototyped feedthrough glass wafers were subjected to anodic bonding to a silicon wafer with diaphragms. The anodic bonding was successful, but hermetic sealing was not achieved. Also, the bending of the bonded sample is large in the direction of stacking of the original glass wafers. The causes of these problems were investigated, and the solution was proposed.